Atherosclerosis is a disease that involves the deposit of lipids, with an especially high concentration of cholesterol, on the walls of the large arteries. Often, calcium precipitates the lipid build-up to form calcified plaques which leads to arteriosclerosis, more commonly known as "hardening of the arteries". The seriousness of this disease is evident from the fact that it is the cause of death for almost half of the human population. Although the cause of atherosclerosis can be attributed to a number of factors, it is clear that a diet which is high in cholesterol substantially increases one's chances of developing atherosclerosis.
In an attempt to prevent atherosclerosis and associated heart disease, cholesterol-lowering drugs have been developed and are currently widely prescribed. The drugs at the forefront of this market incorporate compounds belonging to the "statin" family. These include pravastatin (Bristol-Myers Squibb Company), simvastatin (Merck and Company) and cerivastatin (the Bayer Group). This group of compounds are potent inhibitors of cholesterol synthesis and function by inhibiting HMG CoA reductase, an enzyme that catalyzes the synthesis of a precursor to cholesterol. Not only may such drugs have serious side effects, they do not function in any way to control the intake of cholesterol through diet. They function only to prevent the internal synthesis of cholesterol synthesized primarily by the liver.
Since the 1950's, plant sterols such as sitosterol, stigmasterol and campesterol have been added to patients' diets to treat hypercholesterolemia, a condition of elevated blood cholesterol levels. U.S. Pat. No. 5,244,887, issued to Straub Sep. 14, 1993, discloses a method for making a food additive composition useful to reduce cholesterol absorption from foods and beverages. The composition contains stanols, derivatized forms of sterols, and specifically, contains a stanol selected from the group consisting of clionastanol, 22,23 dihydrobrassicastanol, campestanol and sitostanol, admixed with an edible solubilizing agent, an antioxidant and a dispersant.
U.S. Pat. No. 5,502,045, issued to Raision Tehtaat Oy A B Mar. 26, 1996, teaches the use of a beta-sitostanol fafty acid ester that is also useful to reduce serum levels of cholesterol in patients by inhibiting cholesterol absorption. The active sitostanol ester is prepared from naturally occurring plant sterols derived from green plants and trees, particularly pine trees. At present, however, it is difficult to acquire the essential naturally occurring ingredients in quantities large enough to satisfy the market demand and this poses a significant drawback to products of this nature. Moreover, a further disadvantage of these plant sterols, and particularly those derived from pine trees, is the presence of an unpleasant "pine cone" taste in edible products incorporating a cholesterol-reducing sitostanol ester.
Due to the prevalence of coronary disease in our society, there remains a need to develop novel treatments which overcome the disadvantages of those presently on the market. Of particular interest are products which are therapeutically useful at the nutritional level so as to minimize the uptake of cholesterol and prevent the development of heart disease or conditions leading to it. It is an object of the present invention to provide such a preventative therapy, particularly to those at high risk of coronary heart disease.